Polybutylene terephthalate (PBT) is a semi-crystallographic engineering plastic, possessing a good mechanical property, an electrical property, heat resistance, chemical resistance and the like, and it is extensively applied in industries such as automobile, electronic and electrical appliances. However, still there are drawbacks in PBT, for example a poor flowability and poor injection molding appearance quality of a PBT injection molded part, thus limiting the application of PBT in the above-mentioned industries.
Under a condition that the mechanical and processing properties of a PBT material are not influenced, it has been always a difficult problem in the industry to make the injection molded part satisfy a requirement of improving the flowability and the appearance quality.
So far, there's no report about an influence of a content of tetrahydrofuran on the flowability and the injection molding appearance of the PBT composition.
Through a large number of experiments, the inventors surprisingly found that when the content of tetrahydrofuran which is selected to be added in a formula of a glass fiber-reinforced flame retardant PBT composition, is less than/equal to 500 ppm and more than/equal to 10 ppm based on a total weight of the glass fiber-reinforced flame retardant PBT composition, the flowability and the injection molding appearance of the glass fiber-reinforced flame retardant PBT composition can be apparently improved.